1. Field of the Invention
The present invention relates to a Digital-to-Analog (D/A) conversion, and more particularly, to a D/A conversion method and a D/A converter for converting an m-bit digital signal with an n-bit D/A digital converter.
2. Description of the Related Art
Recently, great progress has been made in digital processing techniques for conventional analog processing systems, such as mobile phones, digital cameras and network phones. Digital-to-analog (D/A) converters capable of converting digital signals into analog signals are required for such digital processing systems.
FIG. 1 shows a traditional D/A conversion. By inputting m-bit data into a m-bit D/A converter, (ex: R-2R ladder D/A converters for example). The m-bit data is converted to corresponding analog data by the internal circuit of the m-bit D/A converter 1. The required circuit area will be much larger, however, if the bit number of the input digital data of the D/A converter 1 is increased. For example, if the bit-number of the input digital data is increased from m to m+1, an m+1-bit D/A converter must be used to receive the m+1 digital data. Hence, the circuit area must be larger.